1. Field of the Invention
This invention relates to the field of vacuum cleaners, and more particularly, to vacuum cleaners of small physical size that are especially constructed and arranged for the cleanup of wet or dry radioactive materials within a small workspace enclosure, such as a glove box.
2. Description of Related Art
Cleanup of radioactive material is addressed in the art. For example, U.S. Pat. No. 4,061,480 provides a vacuum cleaner having a head section housing a motor and a fan. The head section sits on top of a filter unit comprising a filter cartridge, and a bag that comprises a primary filter for the cartridge. The filter unit is contained within a bladder that is impervious to air. Intake to the cleaner comprises an intake port connected to the area enclosed by the bladder. In this way, the material collected by the vacuum cleaner may be disposed of by unitary removing of the bladder and the filter unit.
The problem of hazardous material cleanup of wet or dry material has been addressed in the art. For example, U.S. Pat. No. 4,894,881 provides an open top base reservoir that contains a collection bag, the collection bag being used only for dry cleanup situations. An adapter unit sits on top of the base member. The upper portion of the adapter unit contains a vacuum motor that draws air from within the collection bag, first through a cloth filter bag, and then through a HEPA filter. A ball valve is positioned between the collection bag and the cloth filter bag to interrupt air flow when the base member is full of wet material.
Other patents of interest are U.S. Pat. No. 2,721,625 which describes a compact canister type vacuum cleaner having an upper shell that contains a motor and a fan. A lower shell contains an air inlet and a removable paper bag primary filter. Intake air first passes through the primary filter, then passes through a cloth bag secondary filter, and then passes through an air purifying germ trap comprising a fine mesh screen and fabric. Air then passes through the motor/fan to an exhaust outlet. U.S. Pat. No. 3,343,344 describes a canister-type vacuum cleaner having a lower pan-like container that includes an air inlet opening. A motor/fan unit projects downward into this container. A rigid conical support and its conical paper filter are located intermediate the motor/fan unit and the interior of the container. An air impervious polyethylene bag separates the conical filter from the interior of the container, so as to facilitate removal of the filter and its bag, along with accumulated dust, and the like. Means are provided to equalize the air pressure between the inside and the outside of the bag, so as to prevent collapse of the bag against the conical filter. U.S. Pat. No. 3,961,921 is generally similar in that it describes a shop-type vacuum cleaner having an open top air impermeable bag that is removable to facilitate unloading of the vacuum cleaner. A means is provided to prevent collapsing of the bag against a motor/fan assembly.
While these devices are generally suitable for their diverse intended purposes, the need remains in the art for a critically safe volume vacuum cleaner or pickup for use in the wet, or dry, cleanup of small radioactive workspace enclosures such as glove boxes. Particularly, the need remains for a vacuum pickup having utility in the pickup of plutonium 239 oxide, and which does not require the use of neutron absorption devices such as the well known boron Raschig rings.